1. Field of the Invention
The invention relates to systems including reaction injection mixing apparatus and computer control means associated therewith for producing polymer mixes for molding foamed or unfoamed plastic products, in which programmable control of the mixing and molding functions effected by the pumping and metering equipment involved is employed, and in which a novel design of reaction injection mixing head is utilized to improve high speed automated production of parts on commercial scale without sacrifice in maintaining given physical specifications of each molded part even though successive parts may be of different shape, size or composition.
2. Description of the Prior Art
The reaction injection mixing (RIM) heads disclosed in U.S. Pat. Nos. 4,099,919, issued July 11, 1978 and 4,070,008 issued Jan. 24, 1978, both assigned to the assignee hereof, are representative of the presently known prior art most relevant to the mixing head here disclosed. With the dictates presently made for higher production speeds and greater flexibility for changing mix formulations between successive, closely spaced, molding cycles in a continuously moving commercial molding operation, the RIM equipment heretofore available has not been completely satisfactory. It is accordingly a principal objective of the system here disclosed to provide substantially improved equipment and operational control in order better to meet the needs of modern commercial requirements.